Climate: Did a giant meteor trigger the holocene era?

FRISCO — A meteor that crashed into the ocean about 2.5 million years ago may have had a much bigger effect on Earth’s climate than has previously been acknowledged.

The impact of the mountain-size chunk of space flotsam — the Eltanin meteor — may have injected massive amounts of water vapor, sulfur and dust into the stratosphere, shifting the planet’s climate into fast-forward from the Pleistocene into the Holocene era.

Goff challenged other researchers to take a new look at sediments and other geological features in Chile, Antarctica, Australia, suggesting that the deposits may have been the product of a mega-tsunami caused by the impact of Eltanin meteor.

“As a ‘cene’ changer – that is, from the Pliocene to Pleistocene – Eltanin may have been overall as significant as the meteor that took out the non-flying dinosaurs 65 million years ago,” Goff said.

Goff and his team of Australian researchers said that, because the Eltanin meteor — which was up to two kilometres across — crashed into deep water, most scientists have not adequately considered either its potential for immediate catastrophic impacts on coastlines around the Pacific rim or its capacity to destabilise the entire planet’s climate system.

“But consider that we’re talking about something the size of a small mountain crashing at very high speed into very deep ocean, between Chile and Antarctica. Unlike a land impact, where the energy of the collision is largely absorbed locally, this would have generated an incredible splash with waves literally hundreds of meters high near the impact site.

“Some modelling suggests that the ensuing mega-tsunami could have been unimaginably large – sweeping across vast areas of the Pacific and engulfing coastlines far inland.

“The tsunami alone would have been devastating enough in the short term, but all that material shot so high into the atmosphere could have been enough to dim the sun and dramatically reduce surface temperatures. Earth was already in a gradual cooling phase, so this might have been enough to rapidly accelerate and accentuate the process and kick start the Ice Ages,” Goff said.

In the paper, Goff and colleagues from UNSW and the Australian Nuclear Science and Technology Organisation, said geologists and climatologists have interpreted geological deposits in Chile, Antarctica, Australia, and elsewhere as evidence of climatic change, marking the start of the Quaternary period. An alternative interpretation is that some or all of these deposits may be the result of mega-tsunami inundation, the study suggests.

“There’s no doubt the world was already cooling through the mid and late Pliocene,” says co-author Professor Mike Archer. “What we’re suggesting is that the Eltanin impact may have rammed this slow-moving change forward in an instant – hurtling the world into the cycle of glaciations that characterized the next 2.5 million years and triggered our own evolution as a species.”